Download Attachment adds a cookie in header.

I've developed an external application(frontend with angularJS) using alfresco as backend, n which I provided feature of file upload and download,while downloading the attachment(by creating custom webscript to download the attchment var downloadUrl = node.downloadUrl;).So when I hit this it request using that download URL, it adds a cookie of JSSONID in header,so at any next request it gets failed and gives me an error code 401 unauthorized.what could be the issue, or how can I disable cookie in alfresco.